.outer{
    margin-left:auto;
    margin-right: auto;
    background-color: #dddddd;
    overflow:hidden;
}
.img,.outer{
    width:600px;
    height: 338px;
}
#img-1{background-image: url("../img/123/1.jpg");}
#img-2{background-image: url("../img/123/2.jpg");}
#img-3{background-image: url("../img/123/3.jpg");}
#img-4{background-image: url("../img/123/4.jpg");}
#img-5{background-image: url("../img/123/5.jpg");}
.img{
    float: left;
}
#banner{
    transition: margin-left 1s;
}

